Pressure-indicator



J. A. GREEN.

PRESSURE INDICATOR.

APPLICATION FILED FEB. 25, I919;

7 6 z m U a P 7.

m ;v4 m i P l W JOSEPH A. GREEN, OF PROVIDENCE, BHODE ISLAND.

ranssunammcaron.

Specification of Letters Patent.

Patented Apr. 27, 1920.

Application filed February 25, 1919. "Serial No. 279,082. I

To all whom it may concern Be it known that I, JOSEPH A. GREEN, acitizen of'the United States, and a resident of Providence, RhodeIsland, whose postoffice address is No. 393 Harris avenue, Providence,Rhode Island, have invented an Improvement in Pressure- Indicators, ofwhich the following description, in connection with the accompanyingdrawings, is a specification, like letters onthe drawings representinglike parts.

My present invention is a pressure indicator of the type known assphygmomanometers which are extremely sensitive instruments andespecially adapted for the purpose of testing blood pressure for medicalwork.

An'important object of'the invention is to provide improved meanstofacilitate the assembling and adjustment of this type of indicatorsand also to have the same capable of correct adjustment relatively withthe dial, so that the indicator will register at zero. Heretofore, ithas been customary,

in assembling a delicate pressure mechanism, as herein described, to.vary the position of the dial with the indicator and in fact speciallygraduated dials have frequently been necessary. By the presentinvention, I am enabled to utilize a standard dial and to accuratelyadjust the diaphragm and other operating parts of the mechanism to acorrect reading or registration with the dial. As the moving parts of anapparatus of this type are extremely small, delicate and fragile, theassembling and adjustment is a matter of the greatest importance, bothin the manufacturing expense and also in the subsequent use of asphygmomanometer. I therefore provide adjustable devices and preferablya plurality of adjustable elements enabling the apparatus and dial to beset relatively with each other in order to correspond and register. Amost important feature of the present invention consists in the novelarrangement of means whereby the diaphragm is maintained under aconstant tension, and preferably this tension is adjustable andtherefore one of the means for adjusting the moving parts of thepressure indicator to register with the dial. This feature of having atension orf the diaphragm and referably an adjustable spring tension,ren ers the actuation of the diaphragm more perfect, more uniform, and

also more accurate, preventing uneven variations. I believe that thisfeature of havmg a diaphragm under spring tension is a distinct noveltyand as this is of importance, both in the operation of the gage and inthe adjustment of the same during assembling, I desire to claim the samebroadly.

A further feature of the present inventlon consists in the provision ofautomatic means to prevent any binding, undue strain, fr1ction, or thelike, during the operation of the moving parts connecting the diaphragmwith the indicator and particularly to allow for adjustment of theseconnections during assembling. To this end I- provide an adjustablefriction nut on the diaphragm and I also provide a special type ofadjustable and rotatable device on the gear actuating the indicator,-which rotatable device is connected with the friction nut in a manner totransmit the variations in the diaphragm to the gear without binding'orany undue tension.

Further features of the present inven tion consisting in novelcombination of parts, improved-details of construction and advantageswill be hereinafter more fully pointed out and claimed. 1

Referring to the drawings illustrating a preferred embodiment of theinvention- Figure 1 is a view of my improved pressufie gage, partlyshown in cross section; an

Fig. 2 is an enlarged cross sectional view of the adjustable andswiveling construction on the actuating gear.

While pressure indicators embodying the tionis particularly intended fora sphygmomanometer or other low pressure gage and therefore is ofrelatively small size and extremely delicate in operation, being infact, smaller than the attached drawings and approximately an inch and ahalf in diameter, compactness being of great importance.

The indicator 1 may be of usual type in which a dial 2 is fitted tocotiperate with a hand 3 mounted upon a shaft 4;, which shaft isimpelled in one direction by a coiled hair spring 5. bottom plate 6 andtop plate 7, suitably secured to the casing 1, constitute bearings forthe shaft 4, which carries a pinion, shown in dotted lines at 8, in meshwithyan actuating gear 10-pivoted at 11 in suitable bearings in theplates 6 7. At-

tached .to "the indicator 1 isa diaphragm casing 15, a suitable recessor passage 16 extending from the interior of the casing 15 to the:interior'of the indicator 1 being provided. The diaphragm, designated.generally at 20, comprises a series of disks, preferably of phosphorbronze or other suitable material, such disks being herein illustratedbetween the top disk and bottom disk.

22, the latter being secured to the hollowsleeve 23, by soldering or inany other suit.- able manner. This sleeve is externally threaded asshown at 24, to receive the base of cover 2'5. This cover is threadedonto the stem 23 and is rigidly secured in desired position by a setscrew 26. I prefer to form this. cover also threaded externally 30, thehead 31 being preferably cup-shaped sli htly to present a rim-likecontact, as in icated at 33 with-the inner surface of the disk 21. Thestem 30 is threaded and receives on the outside of the-disk, a. washer34-and threaded nut 35. This construction enables me to form an airtight union between the head of the stem 30 and the top disk 21 withoutsoldering, welding, or other methods of construction. In extremelydelicate instruments of this type, this constructional feature is. ofparticular he ortance and simplifies the assembling and t erefore theexpense of manufacture. The recess 16 between the casing 15 and theindicator 1 is of greater diameter than that of the stem 30 and issufficient to receive,: freely, an adjustablefriction nut 36 threadedonto the stem 30 and having in its u per face a cupshaped bearing 37adapte to receive the comcal end of a link 38. This link is pivotallysecured at 39 toa rod 40, said rod being adjustably and rotatably heldto a block 41, rigidly attached to the gear 10. I prefer to form the rod40 with a shoulder 42 adapted to bear against the edge of the collar 45secured thereto by a set screw,

just'in contact with the edge of the bushin 43 so as to permit arotative movement 0 the rod 40 within the bushing, while also permittingadjustment of both rod and bushing forwardly and backwardly in the'block 41. This construction provides a double adjustment in theconnecting members between the diaphragm and the actuatinggear 10allowing for positioning the pivot 39 at any desired point radially.

from the center 11 of the gear 10 and also by adjustment of the frictionnut 36.

The construction thus far described is operable and the feature ofhaving the mem-' ber 40 both adjustable and swiveling preventing anybindin the transmission o movement from the diaphragm to the ar 10 isof-very great importance in as licate a device as that in this type ofindicator. Themovement under a spring tension wi 1- now be or unduefriction in of the top disk 2,1. Rotation of-this shaft 50 thereforeserves to compress the spring '51, after it has contacted with the head31, to a desired degree of tension, thus smiultaneously uttihg theentire diaphragm under a pre iminary tension and also con stituting anadjustment to locate the hand 3 at zero on the dial 2, a slight increaseor:

decrease on the spring 51' through manipulation of the shaft 50 thusaccomplishing both these features. value in practice since theadjustments of the rod 40 and the friction nut 36- give a preliminarycapability of adjustment during the assembling of the pressure gage andThis is of considerable the further manipulation of the threaded" shaft50, thus serves as a finer and .finaladjustment of the hand 3 whilelacing the. 11 order to diaphragm under the tension. hold and locktheshaft 50 into where'thus adjusted, I provide a t readed osition lockingnut 52 and in order, to still further 1 V complete the apparatus and toprevent disv arrangement of either the locking nut 52 guardthe same andto which the rubber or shaft 50, I provide a threaded cap 55 to tube tothe pump and band may be attached.

The operation of my improved-indicator will be readily understood. ;Thevarlous delicate parts, connections, andmechanisms can be easilyad'usted and quickly assemr bled. With the iaphragm 20 subject to the Itension of the sprin 51 at the beginning.

and during any in eating ,operation, the

' movement of the diaphragm is steadied and rendered more uniform andmore delicate,

the inherent resiliency of the diaphra being thus guided and controlled.W1th the two springs 5 and 51 also actuating in accurate holding of thehand 3 and consequently an easier and quicker reading of'the indicatorresults with greater freedom from opposition to each other, a more.steady and error. The swiveling Operation of the rod eliminates anydanger .of binding 1nthe connections from the-diaphragm to'the gear 10and thereby still further renders the 1n'-' strument accurate during alarge range of pressures and irrespective of the relative position ofthe block 41 on the gear 10, as it is swung upwardly ordownwardly. Itwill be appreciated therefore that I have provided a novel and efficientindicator, with a most accurate capability for adjustment in assemblingand in operation, enabling a standard dial to be used and-with the zeroalways positioned at the same place and also, with the two springsacting against each other, a steadying means for the hand during theoperation of the apparatus.

My present invention is further described and defined in the form ofclaims as follows:

1. In a pressure indicator of the kind described, a dial, an indicatinghand arran ed for rotative movement over said dial, a iaphragm adaptedto recelve variations 1n fluid pressure and means to transmit thevariations in movement in said diaphragm to the indicating hand,comprising a gear wheel carrying'a fixed block, a sleeve slidable withinsaid block, a rod adapted to swivel within said sleeve and a movablelink from said rod to a member carried by the diaphragm.

2. A pressure gage'of the kind described -having in combination adiaphragm, an inconnections from the diaphragm to the indicating hand,whereby movement .of the former will be communicated to the latter,including a cup-shaped member adjustably secured to a threaded stemrigid with the diaphragm, said member having friction engagement withsaid stem to hold the same Wherever adjusted.

4. A. disk diaphragm of the kind described having in combination a basehaving an interiorly threaded bore, a threaded shaft adapted to rotatewithin said bore, a spring carried by the shaft and arranged to exertyielding tension on the top disk of the diaphragm and means to' locksaid spring and member into finally adjusted position. In testimonywhereof I have signed my name to this specification in the presence oftwo subscribing Witnesses.

JOSEPH A. GREEN. Witnesses:

' JAMES R. HODDER,

RACHAEL L. CLARK.

